[U-Boot] [U-Boot,v2 6/6] sf: Set QUAD enable bit support

[Jagannadha Sutradharudu Teki]

This patch provides support to set the QUAD enable bit on flash.

QUAD enable bit needs to set before performing any QUAD IO operations
on respective SPI flashes.

User need to use spi_flash_set_quad_enable_bit() to set the
QUAD enable bit based on their usage.

Signed-off-by: Jagannadha Sutradharudu Teki <jagannadh.teki at gmail.com>
---
Changes in v2:
        Improved code logic

 drivers/mtd/spi/spi_flash.c          |   31 +++++++++++++++++++++++++++++++
 drivers/mtd/spi/spi_flash_internal.h |    4 ++++
 2 files changed, 35 insertions(+), 0 deletions(-)

diff --git a/drivers/mtd/spi/spi_flash.c b/drivers/mtd/spi/spi_flash.c
index 5bddde4..675a0bf 100644
--- a/drivers/mtd/spi/spi_flash.c
+++ b/drivers/mtd/spi/spi_flash.c
@@ -329,6 +329,37 @@ int spi_flash_cmd_read_config(struct spi_flash *flash, void *data)
 	return 0;
 }
 
+int spi_flash_set_quad_enable_bit(struct spi_flash *flash)
+{
+	u8 data = 0, write_done = 0;
+	int ret, pass;
+
+	for (pass = 0; pass < 2; pass++) {
+		ret = spi_flash_cmd_read_config(flash, (void *)&data);
+		if (ret < 0) {
+			debug("SF: fail to read config register\n");
+			return ret;
+		}
+
+		if (data & STATUS_QEB) {
+			debug("SF: quad enable bit is set.\n");
+			return ret;
+		} else if (write_done != 1) {
+			debug("SF: need to set quad enable bit\n");
+
+			write_done = 1;
+			ret = spi_flash_cmd_write_config(flash, STATUS_QEB);
+			if (ret < 0) {
+				debug("SF: fail to write quad enable bit\n");
+				return ret;
+			}
+		}
+	}
+
+	debug("SF: fail to set quad enable bit\n");
+	return -1;
+}
+
 /*
  * The following table holds all device probe functions
  *
diff --git a/drivers/mtd/spi/spi_flash_internal.h b/drivers/mtd/spi/spi_flash_internal.h
index 844e82e..15c7ac4 100644
--- a/drivers/mtd/spi/spi_flash_internal.h
+++ b/drivers/mtd/spi/spi_flash_internal.h
@@ -31,6 +31,7 @@
 
 /* Common status */
 #define STATUS_WIP			0x01
+#define STATUS_QEB			0x02
 
 /* Send a single-byte command to the device and read the response */
 int spi_flash_cmd(struct spi_slave *spi, u8 cmd, void *response, size_t len);
@@ -87,6 +88,9 @@ int spi_flash_cmd_write_config(struct spi_flash *flash, u8 cr);
 /* Read the config register */
 int spi_flash_cmd_read_config(struct spi_flash *flash, void *data);
 
+/* Set the QUAD enable bit */
+int spi_flash_set_quad_enable_bit(struct spi_flash *flash);
+
 /*
  * Same as spi_flash_cmd_read() except it also claims/releases the SPI
  * bus. Used as common part of the ->read() operation.
-- 
1.7.0.4